The research conducted in patents of similar systems shows that the process of interposing a colourful liquid between two transparent surfaces appears in systems that fill up from the bottom but do not allow uniform darkening.
In these systems the window works as a thin tank partially filled with a clear upper area and a dark inferior area. Moreover, as the distance between the two glasses is constant when the liquid is removed phenomena of condensation may occur, which makes visibility difficult.
DE 29809846, DE 4127130, EP 0445314, EP 0402529 e DE 3942677) may be included in this group.
In WO 9206266 (FR 2667349) and FR 1379026 the transparent plates are assembled by an elastic joint whose length allows the glasses to withdraw from each other. In the case of our claimed system, the flexible membrane will only have to make a slight angle between the two extreme positions from transparent to totally opaque. The membrane that assembles the fixed part to the movable one can be strengthened with a textile to support the pressure of the liquid column, which wouldn't be possible according to the systems foreseen in WO 9206266 e FR1379026 that require the elastic deformation of the joint. In spite of the referred alteration which assures a much higher resistance of the flexible joint, the system now claimed, opposite to the description of previous documents, works under a pressure lower than the atmospheric pressure in order to partially compensate the effect of the liquid column and the huge strength exerted on the bottom of the window which otherwise would cause a tremendous bend of the transparent plates even if very thick laminated glasses were used.
The present invention thus solves the problem of the window's height limitation since it allows the compensation of the pressure of the liquid through the vacuum existing in the liquid reservoir. That is not possible in the abovementioned documents, as it is recognised in WO 9206266 that mentions the need of thick glasses (10-12 mm) for a window comprising 2 square meters.
The broad strength exerted by the liquid on the base of the vertical sets would, indeed, block the use of elastic solutions despite being disclosed in WO 9206266 and FR1379026.
The systems designed in WO9206266 and FR1379026 patents were projected as mere ways of controlling of light and not as energy collectors which makes a relevant difference. The system now claimed is intended for collecting solar energy unlike WO 9206266 which tries to avoid heating the liquid using reflective films on the glasses.
Concerning the document CA 2077502 it is shown that this is not a system to collect solar energy once nothing is projected to cool the liquid. This patent foresees a fixed spacing of about 0.5 to 1 mm between glasses, i.e., it doesn't allow a gradual variation of light as the claimed system does.
As in the above referred patents, the system suggested in CA 2077502 will only permit to build windows higher than 50 cm using very thick glass to compensate the pressure of the liquid.
EP 0358807 allows a variable spacing between the glasses through a mechanical process using the manual actuation of eccentric parts that press one of the glasses, showing a very different way of functioning from the claimed system.
WO 2000012857 describes a system of transparent plates at a fixed distance whose space can be filled up with a colourful liquid which expands inside elastic reservoirs. Its conception is incompatible with windows of great dimension due to the pressure exerted by the liquid on the elastic reservoirs which have to be flexible enough to absorb the dilation caused by heating. Likewise progressive and continuous darkening is not possible either.
Among patents of window systems intended for energy absorption, there is WO2001063061 which describes a system where transparent panels are used to cover building facades so that solar energy can heat the colourful fluid between the plates. The system has to continuously allow the light flow since no change in the thickness of the film (or in the composition of the fluid) is admitted. It is, indeed, a system of constant thickness which can neither replace Venetians or blinds nor control the light flow as the systems herein claimed.
U.S. Pat. No. 4,380,994 disclose a system of energy absorption composed by two chambers where a liquid can be inserted. In order to feed the fluid, a chamber placed outside the building will be used to absorb solar energy during summer, dissipating it to the exterior.
In the winter the liquid would be placed in an interior chamber, from where the energy absorbed will be radiated to the inner space of the building, working as a heating system. The system consists of two chambers separated by a fixed space, but it doesn't allow the continuous control of light flow nor will it be able to work during the summer as an energy collector since it is intended to enable energy dissipation avoiding heating the building.
The system disclosed in U.S. Pat. No. 4,561,221 comprises glasses with a fixed distance between each other, wherein a liquid flows aiming to prevent a room temperature rise. This system is therefore destined for energy dissipation and does not allow a control of sunlight admission inside the building.
Electric Systems
Many systems of patented intelligent Windows use photochromic or electrochromic effects with electrically conductive ion layers whose working principles are similar to those used in the technology of liquid crystal, electromagnetic processes that act on anisotropic particles, or use working principles of radiation absorption but are unable to collect thermal energy.
The use of solar energy for heating is generally carried out by placing solar collectors on roofs. The system now proposed can function as a skylight to control light intensity, or as a window or even a door. Part of the frame structure and glazing has its traditional role but includes, as well, two other new functions: as a curtain and as energy collector. The claimed system, although more complex than the traditional solutions, offers the possibility to grade the light flow, and turn a room into a completely dark space. There will also be the possibility, if connected to a sensor, to adapt it to the solar variations in order to allow a constant illumination level.